3 HP Frisco Standard Stationary Single 4-Stroke IC Engine

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3 HP Frisco Standard Stationary Single 4-Stroke IC Engine

Home Forums CAD – Technical drawing & design 3 HP Frisco Standard Stationary Single 4-Stroke IC Engine

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  • #527370
    Andy_G
    Participant
      @andy_g
      Posted by PatJ on 14/02/2021 18:10:05:

      1. Will two helical gears mesh and operate properly at 90 degrees if the angle is not 26.6 and 63.4, as long as the sum of both angles equals 90 (yes/no) ?

      Yes.

      The 'magic' helix angles give two gears that will mesh at 90 degrees with the same PCD, but one being twice the number of teeth than the other (2:1 gear ratio).

      If both are 45 degree helix angle, for example, the larger gear will be twice the diameter of the smaller for a 2:1 ratio.

      Gear ratio is all about the number of teeth, nothing else.

      Gear diameter (for a given module / DP) is determined by no. of teeth *and* helix angle.

      For skew helical gears to mesh, they must have the same *normal* module.

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      #527377
      PatJ
      Participant
        @patj87806

        Thanks much Andy and Jason-

        More ideas to consider.

        I am hoping that a light bulb will pop on in my head, and it will all be clear, but at this point is it about half clear, half muddy water.  I expected this to be crystal clear to me a long time ago, but alas it has not crystallized yet.

        I will ponder this geometry and pray for an inspiration in math.

        Its not like I don't do math, or can't do math (I can, and I do use math every day).

        Its just trying to get a visual representation of what is happening with the motion, and how that related to spur gears, worm gears, gears in general, and helix gears in particular.

        The 3D modeling helps immensely from a visual standpoint, and helps visualize machining too.

        I just need to study the geometry a bit more.

        Thanks again to all for suffering me on these endless questions.

        I do appreciate it very much.

        .

        Edited By PatJ on 15/02/2021 00:37:17

        #527506
        PatJ
        Participant
          @patj87806

          I did more research last night, and also have been studying the spreadsheet that Rod sent.

          It is interesting to see which helical gears are available commercially.

          The inch crossed gears available here are somewhat limited, and they all have a 45 degree helix angle.

          The metric teeth go by "module", and there is much more of a selection in metric.

          All the metric gears have a 21.5 degree helix angle.

          Information from McMaster-Carr:

          For gears to mesh correctly, they must have the same pressure angle and pitch.

          To change speed and torque, pair two gears with different numbers of teeth.

          Crossed helical gears, also known as screw gears, can be configured to transmit motion at a 90 degree angle if paired with the same tooth direction.

          Another supply site give a series of boxes on the left side of the page, and you can go down the list and select the parameters you desire.

          It is interesting to note that as I go down the list and select module, and number of teeth, the list of available gears becomes identical for everything except bore diameter and left/right hand.

          I mentioned this earlier, that if one were using commercial gears for the Frisco Standard, one would have to select the gear pair first, determine their center-to-center dimension, and then scale the engine design up or down to fit this dimension, which may give a very odd scale factor (I don't always use standard scale factors anyway, but just saying the design has to start with the gears and radiate outwards).

          With 3D modeled gears such as the ones Jason sent me, I can scale them with impunity, and I don't have to adhere to any standard module/pitch size, or any standard gear cutter size, assuming I will cast the gears (I will be casting these gears).

          I looked at diagrams indicating the triangle that has been mentioned here several times, and that is slowly starting to sink in.

          So I would guess that the commercial gears that have either the 45 degree angle, or the metric with the 21.5 degree angle will mesh if they are the same module/pitch, (both must be either 45 or 21.5 degrees of course), and the same diameter gears will produce a 1:1 shaft speed ratio.

          Changing shaft speed or torque with commercial helical gears seems to indicate that the tooth ratio dictates the speed ratio, since the angle is fixed for all the gears.

          So it would seem that our gear example of two helical gears with the same diameter and differing too count is a bit of an oddball compared to what can be found in the commercial world ?

          There is no doubt that Jason's gears work; I have the 3D prints in hand, and they do indeed mesh perfectly.

          I have to guess that this configuration is perhaps not very suitable for any significant power transmission, and I think I have read that on some of the gear sites.

          This is a fascinating study in gear geometry and gear terminology.

          I played around with cutting one spur gear a few years ago, but I had no idea there was such a variety of gear types, and no idea that there could be so many variations within just the helical gear type.

          This is a rather eye opening experience for me.

          I must say I feel rather insignificant by being ignorant of most gear technology, but I am slowly catching up, and I think I will get there at some point as far as a good working understanding of helical gears and how they mesh/operate.

          If my proposed bound sand method does not work for casting these gears, I will invest in the ceramic slurry process, and purchase some of the type of 3D filament that cleanly burns out.  I do have a burn-out kiln, and so I can do lost-filament castings if I purchase the slurry.  The slurry has a fixed shelf life, so I will have to delay the purchase until warmer weather (if the bound sand does not work).  The slurry cannot be shipped in freezing weather either, since it is water-based.

          Edit:

          9 F here today, and that is without wind chill.

          And it is snowing too.  We very seldom see this kind of weather, and our houses are not designed for this weather.  There are going to be a vast number of broken pipes all over town in a few days.  I added light bulbs to my two outdoor hose bibs, and wrapped insulation over them, since they will freeze the pipes in the wall at this temperature without some heat.

          My friends north of me tell me that 9F is a mild winter for them.

          LOL, glad I don't live up north.  I would not get much casting done.

           

           

          Edited By PatJ on 15/02/2021 15:47:47

          Edited By PatJ on 15/02/2021 15:53:09

          #527563
          Andy_G
          Participant
            @andy_g

            Posted by PatJ on 15/02/2021 15:43:40:

            So I would guess that the commercial gears that have either the 45 degree angle, or the metric with the 21.5 degree angle will mesh if they are the same module/pitch, (both must be either 45 or 21.5 degrees of course), and the same diameter gears will produce a 1:1 shaft speed ratio.

            Yes, two 45 degree helical gears of the same hand will mesh at 90 degrees with crossed axes. However, 45 degrees is something of a special case as both gears in the pair have the same helix angle. Otherwise, the helix angles just need to sum to 90degrees – think of a worm wheel as a single tooth helical gear with a >85 degree helix angle.

            I'm guessing that the 21.5 degree helical gears are intended to mesh on parallel axes (as per spur gears) in left and right handed pairs. If one wished to create a 90 degree drive with these, the matching gear would need to have a helix angle of 68.5 degrees (90-21.5 if I've done my maths correctly).

            I suspect that the reason that only 45 degree skew gears / crossed helical gears are readily available is that the number of other variants would be huge otherwise.

            From the above, it sounds like you are more comfortable with DP than module. I'm the opposite, but will try an example:

            Pitch diameter of a spur gear is [#teeth]/[DP]

            => 60 tooth 40DP spur gear has 1.5" PCD

            Pitch diameter of a helical gear is [#teeth]/([DP] x [Cos(b)]) where b is the helix angle.

            => 60 tooth 40DP 30 degree helical gear has 1.732" PCD

            => 30 tooth 40DP 60 degree helical gear has 1.5" PCD

            Note that [DP] corresponds to the pitch *normal* to the tooth – i.e. on a plane rotated by angle (b) wrt the gear axis. The tooth outline looking down the axis of the gear will not be the same as a 40DP profile (although there is a way of specifying helical gears by this profile, the normal DP (or module) still needs to match for them to mesh).

            If you play with the angles in the 30+60 degree example, you can see that the centre to centre spacing of the pair (sum of PCD/2) can be varied while keeping the same gear ratio and normal DP.

            The contact between the gear teeth is largely sliding so they aren't ideal for transmitting high loads.

            I hope I haven't further confused you!

            #527584
            PatJ
            Participant
              @patj87806

              Thanks for the information Andy.

              I am slowly getting there (I think) with the helix gear thing.

              I have always been a slow learner, and have had learning difficulties (many would say that "learning difficulties" is a polite way of saying I am just dumb; LOL, well it is what it is, call it what you will).

              But I am tenacious, and so like the tortoise and hair story, I will get to the finish line, but I won't be setting any speed records.

              I began college as an ME, but then changed to an EE, otherwise I think I would have mastered this in machine design classes a long time ago.

              It is late in the game for me to start learning gear design, but then again it was late in the game for me to learn Solidworks, and look where I am now.

              I never thought I would figure out Solidworks, but it is second nature to me at this point.

              You never really know what you are capable of without trying and often failing.

              Failure is just an opportunity to learn what you did wrong, and get it right the next time.

              If I live to be 150, I am going to embrace change every day. I don't really have a choice in my field since the changes that have occurred to electrical equipment in the last 35 years are quite dramatic as far as all the electronics that have been added.

              I have to take continuing education classed every year to remain registered, and so change is part and parcel to what I do for a living.

              I read this entire thread again from the beginning last night, and started comparing online formulas with Rods spreadsheet, and things are starting to fit together in this puzzle.

              I think given another 50 years or so, I will have a full understanding of helical gears (LOL, just kidding, I am making good progress).

              Again I really appreciate all the feedback from everyone here.

              This forum group is the best in my opinion; nice folks and knowledge above anything I can find anywhere else in the world. A big hats off to you folks !!!

              I hope to finish up this diversion into helical gear design soon, and get back to the business of making the Frisco Standard.

              .

              Edited By PatJ on 15/02/2021 20:03:38

              Edited By PatJ on 15/02/2021 20:05:01

              #527587
              PatJ
              Participant
                @patj87806

                On the weather side, we have been sitting on 9 F all day with snow.

                Quite unusual for this part of the country. I don't recall ever seeing single digit temperatures around here.

                It will be a bonanza for the plumbers in a few days, as the houses and plumbing around here are not set up for single digit weather. I have heaters on both of my outdoor hose bibs.

                For those who live up north, I am told this is child's play, but it is a significant event down this way.

                We had an ice storm a few days ago, and the trees are still loaded with ice in a dangerous way.

                Ice storms in a city that has a heavy tree canopy can be a deadly thing, and lots of houses get damaged when the big trees and limbs come crashing down.  I don't have any large trees very close to my house, just so that I won't have problems during events like this.

                Needless to say, when things begin to thaw, driving will be a full scale demolition derby.

                ,

                rimg_9025.jpg

                Edited By PatJ on 15/02/2021 20:13:00

                Edited By PatJ on 15/02/2021 20:14:09

                #528340
                PatJ
                Participant
                  @patj87806

                  We are still frozen in here.

                  The snow got significantly deeper yesterday.

                  Some water systems in this region are starting to fail.

                  We still have natural gas, water and power. The water company is beginning to send out ominous warnings about curtailing water usage, so we are stocking up some coolers to store water.

                  We can always melt snow and drink that.

                  I have two generators, so we will be fine as long as we don't run out of gasoline. If the power goes out, so do the filling stations, and so then no gasoline.

                  At that point I would probably pull out my oil burner, and start using that for heat somehow.

                  I have quite a bit of diesel to burn.

                  We don't eat much, and so don't need a huge stock of food. We have some spare food, and a propane cook stove.

                  We also have a fireplace, and in the past during extended ice storm power outages, we have build a fire, and stayed warm that way.

                  We are prepared (as they say in the Scouts), and we have had storms like this in the winter with power out for 10 days.

                  And my wife and I go out hiking in the snow every night for exercise.

                  We walked 2 miles in the snow last night. It was majestic to say the least, and so quiet.

                  The very essence of a "winter wonderland".

                  I am considering building an igloo.

                  .

                  Edited By PatJ on 18/02/2021 18:04:02

                  Edited By PatJ on 18/02/2021 18:05:20

                  #528342
                  PatJ
                  Participant
                    @patj87806

                    I ran across this video yesterday.

                    I can see that I am missing a lot of function by not using equations in Solidworks.

                    There are also a lot of functions that he uses in the video that I do not, such as creating relationships between objects/lines.

                    I really need to get better at Solidworks, since using these functions would save me a great deal of time and grief.

                    And I could make one model of a standard spur gear (as he does), and then quickly change that model for any number of teeth, or make it into a helical gear of either left or right hand.

                    Very nice tutorial.

                     
                    .

                    Edited By PatJ on 18/02/2021 18:12:34

                    #528391
                    PatJ
                    Participant
                      @patj87806

                      All water in a city of 800,000 contaminated.

                      Utility issued a "boil water" warning.

                      Its getting interesting around here.

                      .

                      #528610
                      PatJ
                      Participant
                        @patj87806

                        This has sort of become a storm update post, sorry about that.

                        They are discussing shutting down all water in this city.

                        The infrastructure was not designed for 1 F temps, and they are describing the damage to the water system as akin to what a major earthquake would do.

                        They are calling in the national guard to bring water to hospitals.

                        I told my wife we can always melt snow and drink that.

                        She said "The snow is suppose to melt tomorrow".

                        Ruh rho !

                        We got trouble.

                        .

                        #528612
                        PatJ
                        Participant
                          @patj87806

                          We do have rivers nearby, so I guess we can drink river water.

                          I have filters that I use for backpacking.

                          I guess it would be best to get water from above the local wastewater plant discharges.

                          .

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